Laboratory of Genetics, University of Wisconsin-Madison, Madison, Wisconsin, United States of America.
PLoS One. 2011 Apr 20;6(4):e19020. doi: 10.1371/journal.pone.0019020.
Cell polarity is a very well conserved process important for cell differentiation, cell migration, and embryonic development. After the establishment of distinct cortical domains, polarity cues have to be stabilized and maintained within a fluid and dynamic membrane to achieve proper cell asymmetry. Microtubules have long been thought to deliver the signals required to polarize a cell. While previous studies suggest that microtubules play a key role in the establishment of polarity, the requirement of microtubules during maintenance phase remains unclear. In this study, we show that depletion of Caenorhabditis elegans RACK-1, which leads to short astral microtubules during prometaphase, specifically affects maintenance of cortical PAR domains and Dynamin localization. We then investigated the consequence of knocking down other factors that also abolish astral microtubule elongation during polarity maintenance phase. We found a correlation between short astral microtubules and the instability of PAR-6 and PAR-2 domains during maintenance phase. Our data support a necessary role for astral microtubules in the maintenance phase of cell polarity.
细胞极性是一个非常保守的过程，对于细胞分化、细胞迁移和胚胎发育都非常重要。在建立了明显的皮质域之后，极性线索必须在流动和动态的膜内稳定和维持，以实现适当的细胞不对称性。微管一直被认为传递了使细胞极化所需的信号。虽然先前的研究表明微管在极性的建立中起着关键作用，但在维持阶段微管的需求仍然不清楚。在这项研究中，我们表明，秀丽隐杆线虫 RACK-1 的耗竭会导致前期中期的星状微管变短，这会特异性地影响皮质 PAR 域和 Dynamin 定位的维持。然后，我们研究了敲除其他也会在维持极性阶段消除星状微管伸长的因子的后果。我们发现，在维持阶段，短的星状微管与 PAR-6 和 PAR-2 域的不稳定性之间存在相关性。我们的数据支持星状微管在细胞极性维持阶段的必要作用。
